In general, a 3D pointing device is used as an input unit to input the command of a user into a central processing unit (central processing part) of a computer body. The operation of the 3D pointing device is re-produced by a pointer (called a cursor of a mouse), which is moved to the position of a required command contained in a basic menu screen image to select the required command, in the state that the basic menu screen image is displayed on the screen of a display such as a cathode-ray tube or a monitor. The pointer is a medium which selects one from a plurality of commands of a menu screen image by re-producing the movement of an electrically and mechanically-structured hardware, which serves as the 3D pointing device, on the screen image of a display device in real time and inputs the selected command into the central processing part.
The position of each command displayed on the menu screen image is memorized as related data in the central processing part. The movement position of the pointer to transfer the command is recognized as the movement position in x and y axes (which serve as horizontal and vertical directions) by the central processing part. In this case, the execution of an algorithm related to the command selected by the pointer is determined in the central processing part depending on if the position of the pointer is matched with the position of the selected command. In the same manner, the user can easily and conveniently input the command of the displayed menu screen image while freely moving the 3D pointing device.
However, when a user grips the body of the 3D pointing device with the hand and performs pointing to an indication point, the indication point may be shaken due to the shaking of the user hand.
In particular, when one point is indicated through the 3D pointing device, the angular vibration of the 3D pointing device is caused due to the shaking of the user hand, so that the pointer may be seriously shaken at the final indication point. Accordingly, the contents that the user wants to deliver are not clearly delivered to the audience, and the user or the audience may feel displeasure. Accordingly, the movement of the pointer, which the user does not want, must be distinguished from the movement of the pointer which the user wants.